The printing process of an image forming device, such as a laser printer, includes distributing toner to a recording sheet. The toner is usually a fine powder made of plastic granules that is transferred from a photoconductive drum, or intermediate transfer device, to the recording sheet. The toner is then fixed to the recording sheet by applying heat and/or pressure. In one popular embodiment, the heat and/or pressure is applied through a pair of fuser rollers that are spaced a distance apart between which the recording sheet and toner pass.
Problems may occur when the recording sheet with toner passes through the fuser rollers. One problem occurs when the toner on the recording sheet adheres to one of the fuser rollers resulting in image contamination as the toner does not adhere to the correct location on the recording sheet, or remains on the roller and is not transferred to the recording sheet. Another problem occurs when the recording sheet is inadvertently wound around one of the fuser rollers causing a jam.
To overcome these problems, oil is applied to one or both of the fuser rollers. The oil reduces the amount of toner that adheres to the rollers, and also lessens the likelihood of the recording sheet becoming entangled. An oil applicator is positioned adjacent to the rollers for distributing the oil. However, the application of oil to the fuser rollers may result in additional problems.
One problem is inconsistent oil transfer to the rollers during the life of the oil applicator. Many designs result in an over-abundance of oil being transferred to the fuser roller early in the life of the applicator. Too much oil distributed onto the rollers may be transferred to the recording sheet resulting in oil spots that are visible to the user thereby ruining the sheet. Conversely, the same applicators often do not apply an adequate amount of oil during the end of their life. Inadequate oil results in toner adhering to the fuser rollers and/or the recording sheet sticking to the fuser rollers, both of which are unacceptable results. Inconsistent oil application also makes it difficult to predict the expected life of the oil applicator.
Many currently existing oil applicators are messy to install and remove from the image forming device. One common design features a pad through which oil is applied and then wicked to the fuser rollers. Installation of this type of applicator may require that the pad be doused with oil during the installation which may result in oil contacting the user and also portions of the image forming device which may then be transferred to the recording sheet. Removal of a used oil applicator may again be messy as the oil applicator may be coated with oil that was dispelled during use. The oily applicator may inadvertently contact other parts of the image forming device or get on the user's hands or clothes.
Therefore, there is a need for an oil applicator that coats the fuser roller with a consistent amount of oil during its life, and is not messy to install and remove from the image forming apparatus.